彗星试验检测死后DNA降解推断PMI的参数选择研究

目的筛选出彗星试验检测死后DNA降解推断死亡时间（PMI）的合适彗星参数。方法大鼠断颈处死后置于10℃和20℃环境中44h，每4h取材脑和骨髓组织制成细胞悬液进行彗星电泳，CASP软件测量彗星参数，线性回归分析和比较各参数与PMI的相关关系。结果死后DNA随PMI的延长逐渐降解，彗星头和尾DNA百分比、尾DNA、Olive尾矩、尾面积、尾矩等参数与PMI呈稳定的线性相关关系。结论彗星头和尾DNA百分比、尾DNA、Olive尾矩、尾面积、尾矩等参数是彗星试验检测死后DNA降解推断PMI的合适参数。

Selection of parameters to infer postmortem interval by detecting DNA degradation using comet assay

Objective To select appropriate comet parameters to estimate postmortem interval(PMI) by detecting degradation of DNA after rat death using comet assay.Methods Rats were killed by neck dislocation and then left at 10℃ and 20℃ for 44 hours.Cell suspension was made from brain and marrow at intervals of four hours to do comet assay.Comet parameters were measured by CASP software,and linear regression analysis was made to estimate and compare relation between these parameters and PMI.ResultsDNA degraded gradually as prolongation of postmortem time.There was linear relation between comet parameters(headDNA percent,tailDNA percent,tailDNA,Olive tailmoment,tailarea,tialmoment) and PMI.Conclusion Comet headDNA percent,tailDNA percent,tailDNA,Olive tailmoment,tailarea,tailmoment are the appropriate parameters to estimate PMI through detecting DNA degradation by comet assay.